將20個過載的子文件合併爲一個文件

Question

我正在與一個第三方庫進行連接，這個第三方庫連接到一個舊的數據庫系統。有一種方法 - CallProg，稱爲「存儲過程」（缺乏更好的翻譯 - 人羣中的任何Pick用戶？）。然而，而不是做這樣的事情：

Public Sub CallProg(ProgName, ParamArray ProgArgs() As String) 
    ... 
End Sub 

，甚至這樣的：

Public Sub CallProg(ProgName, Optional Arg1 As String, Optional Arg2 As String ... Optional Arg20 As String) 

他們這樣做：

Public Sub CallProg(ProgName) 
Public Sub CallProg(ProgName, Arg1 As String) 
Public Sub CallProg(ProgName, Arg1 As String, Arg2 As String) 
Public Sub CallProg(ProgName, Arg1 As String, Arg2 As String, Arg3 As String) 
... 
Public Sub CallProg(ProgName, Arg1 As String, ... Arg20 As String) 

我正在寫一個抽象類來處理登錄，設置環境等等，所以它可以在許多其他項目中用作通用的「幫手」類。有什麼辦法可以包裝CallProg的sub，不涉及20個重載？

Answer 1

這是一個非常快速的想法，如何使用反射做到這一點。我不知道，如果它的最好的方式，但它應該工作...

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 

    CallProg("ProgName", {"testArg1", "TestArg2"}) 

End Sub 

Private Sub CallProg(ByVal ProgName As String, ByVal Params As IEnumerable(Of String)) 

    Dim testClass As New Test1 

    Dim methodTypes As List(Of Type) = 
     Params.Select(Function(x) GetType(String)).ToList 

    methodTypes.Add(GetType(String)) 

    Dim methodToBeCalled As Reflection.MethodInfo = 
     testClass.GetType.GetMethod("CallProg", 
            System.Reflection.BindingFlags.Instance Or System.Reflection.BindingFlags.Public, 
            Type.DefaultBinder, 
            methodTypes.ToArray, 
            Nothing) 


    Dim paramsToPass As New List(Of String) 

    paramsToPass.Add(ProgName) 
    paramsToPass.AddRange(Params) 

    methodToBeCalled.Invoke(testClass, paramsToPass.ToArray) 

End Sub 

末級

公共類的Test1

Public Sub CallProg(ByVal ProgName As String) 
    Debug.WriteLine("Sub0 called") 
End Sub 

Public Sub CallProg(ByVal ProgName As String, ByVal Arg1 As String) 
    Debug.WriteLine("Sub1 called") 
End Sub 

Public Sub CallProg(ByVal ProgName As String, ByVal Arg1 As String, ByVal Arg2 As String) 
    Debug.WriteLine("Sub2 called") 
End Sub 

Public Sub CallProg(ByVal ProgName As String, ByVal Arg1 As String, ByVal Arg2 As String, ByVal Arg3 As String) 
    Debug.WriteLine("Sub3 called") 
End Sub 

末級

Answer 2

另一種方式按照Rene147的建議：

Private _act As New APIClass 

Public Sub CallProg(ByVal ProgName As String, ByVal ParamArray ProgArgs() As String) 
    Try 
     Dim tList As New List(Of Type) 
     tList.Add(GetType(String)) 

     Dim aList As New List(Of String) 
     aList.Add(ProgName) 

     For Each arg In ProgArgs 
      tList.Add(GetType(String).MakeByRefType) 
      'tList.Add(GetType(String)) <-- only use this if all the args are ByVal 
      aList.Add(arg) 
     Next 
     Dim typeList As Type() = tList.ToArray 
     Dim argList As String() = aList.ToArray 

     GetType(APIClass).GetMethod("CallProg", typeList).Invoke(_act, argList) 
    Catch ex As Exception 
     Console.Write("Error running program {0}.", ProgName) 
    End Try 
End Sub